RestekCapillaryColumn InstallationGuide, Section II
We recommend placing a throttling valve (needle valve or restrictor) on the carrier gas
inlet bulkhead fitting of pressure-regulated systems to prevent a catastrophic carrier
gas loss should an inlet leak occur. If several GCs are attached to a common carrier gas
source, a leak in one GC could drain the carrier gas from all other GCs, causing a loss of
flow and subsequent damage to all capillary columns in the entire system. To prevent
this from happening, limit the flow of carrier gas to each gas chromatograph (via a
throttling valve) until it matches the flow requirements of the inlet system. This can be
detectedwhen the column's head pressure starts to decrease if the throttling valve is
closed any further.
InjectorMaintenance
Perform injector maintenance prior to installing a capillary column. Periodic
maintenance is required after installation, depending on the number of injections and
the cleanliness of the samples. Maintenance includes cleaning and deactivating inlet
sleeves, replacing critical inlet seals, and replacing the septum. Review the instrument
manual inlet diagram prior to disassembly.
Cleaning andDeactivating Injector Sleeves
Don't install a new Restek columnwith a dirty injector sleeve! For optimum column
performance, the inlet sleeve needs to be free of septum particles, sample residue, and
ferrule fragments. Use deactivated inlet sleeves when analyzing samples with active
functional groups or compounds prone to decomposition or adsorption onto untreated
glass surfaces.
If the sleeve is deactivated and not
excessively dirty, cleaningwith organic
solvents will not affect the integrity of the
deactivation layer. First, use non-swelling
organic solvents such asmethanol or
isopropyl alcohol to remove septum
particles that adhere to the sleevewall.
Next, use solvents such as pentane,
methylene chloride, or toluene to remove
sample residue. Nylon tube brushes and
pipe cleaners (cat.# 20108) are ideal for
cleaning sleeves. Do not use laboratory
detergents, acids, or bases to clean sleeves
because theywill remove the deactivation
layer and require sleeve resilanization.
Sleeves that are very dirty or contain
pyrolyzed residue can be difficult to clean.
Heating borosilicate or quartz sleeves
overnight in amuffle furnace at 550°Cwill
removemost contaminants. Etchingwith a 1:1:1mixture of hydrofluoric acid, sulfuric
acid, and deionizedwater for ten seconds is also very effective. However, heating to
